1. Field of the Invention
This invention relates to a hand tool for driving a fastener about an axis, more particularly to a hand tool with a handle and a bit which is detachably connected to the handle to perform multiple functions.
2. Description of the Related Art
A conventional hand tool, as described in U.S. Pat. No. 5,533,429, is disclosed to include a handle, a handle insert, and a fastener engaging portion which includes an elongated tube and two reversible screwdriver tips to be inserted into the handle insert. The handle insert releasably retains the fastener engaging portion by means of a detent which includes a ball and spring band arrangement for releasably gripping the fastener engaging portion. Such a hand tool is complicated in structure and entails a relatively high manufacturing cost.
Another hand tool, as described in U.S. Pat. No. 5,335,409, is disclosed to include a handle which defines an opening for receiving a bit. The opening has a shoulder for positioning an O-ring between the shoulder and an insert mounted to the handle within the opening. The bit is received in the handle and an opening through the insert such that the O-ring resiliently grips the exterior surface of the shaft of the bit to hold the bit in the handle with sufficient force to permit the bit to be held in the handle when the handle when the handle is grasped by the user during use. Although such a hand tool is simple in construction, there is a need to sleeve the O-ring and the insert on the shaft of the bit before assembly of the bit into the handle, thereby resulting in inconvenience during assembly of the bit.
The object of the present invention is to provide a hand tool which has a simple construction, which is easy to assemble, and which is relatively inexpensive to manufacture.
According to this invention, the hand tool includes a handle, a fastener engaging member, a resisting member, and a bit. The handle includes a first inner surrounding surface which is disposed around an axis and which defines a first bore that axially extends into the handle and that terminates at a blind end. The fastener engaging member includes a second outer surrounding surface to be forced frictionally into the first bore in an axial direction parallel to the axis, and a second inner surrounding surface which is surrounded by the second outer surrounding surface about the axis and which defines second and third bores opposite to each other in the axial direction and proximate and distal to the blind end respectively when the fastener engaging member is received into the handle. An inner peripheral wall extends radially to communicate the second outer surrounding surface with the second inner surrounding surface, and defines a mounting hole. The inner peripheral wall includes two end edge portions which are spaced apart from each other in the axial direction. A deformable member is inserted into the mounting hole in a direction radial to the axial direction, and includes a protrusion which extends in the radial direction and inwardly of the second inner surrounding surface. The resisting member is mounted in the inner peripheral wall to retain the deformable member in the mounting hole against movement in the radial direction when the fastener engaging member has been forced into the first bore, and has an abutment wall surface which abuts against the deformable member radially and inwardly. The bit includes two screwdriver tip ends axially opposite to each other, and a shaft which is disposed between and which interconnects the screwdriver tip ends. The shaft is brought to be inserted into the third bore in the axial direction such that one of the screwdriver tip ends is inserted into the second bore, and such that the protrusion of the deformable member frictionally engages the shaft in the radial direction so as to hinder removal of the bit from the fastener engaging member in the axial direction. A spline member is disposed between the shaft and the second inner surrounding surface to couple the former to rotate with the fastener engaging member when the handle is rotated by the user about the axis.